The present disclosure relates to a sewing machine and a computer-readable recording medium storing a sewing machine control program. More specifically, it relates to a sewing machine that can be used for free-motion sewing and a computer-readable recording medium storing a sewing machine control program for a sewing machine that can be used for free-motion sewing.
Quilting is a conventional sewing method. In quilting, a batting is sandwiched between an outer material and a lining material, and then those materials may be sewn up along a stitch pattern, such as a straight line or a curve. In quilting, there is a case where stitches are formed while a user is freely moving a work cloth manually. Such sewing is referred to as free-motion sewing. In free-motion sewing, stitches may look unattractive if their stitch lengths are not uniform. Therefore, it is desirable to form stitches with a uniform stitch length as much as possible. However, it is difficult for a beginner, who is not skilled in sewing operations, to sew up a work cloth in such a manner as to form stitches with a substantially uniform stitch length while moving the work cloth in a desired direction. To solve this problem, a technique is disclosed in Japanese Patent Application Laid-Open Publication No. 2002-292175 in which driving of a sewing machine is controlled in such a manner as to form stitches with a uniform stitch length by obtaining a movement distance of a work cloth for each stitch, so that the sewing speed may be changed in accordance with the obtained movement distance.
In some cases, a stippling stitch is used in free-motion sewing. A stippling stitch should be disposed evenly within a predetermined region so that a user may enjoy the resulting beautiful design (see FIG. 21). In the stippling stitch, a uniform stitch length is not sufficient to obtain a beautiful result. Like stitch 902 in a predetermined region 901 shown in FIG. 21, a beautiful stippling stitch should create a smooth curve that is disposed within the region 901 in a well-balanced and even manner. The stitch line should not overlap itself, nor should it come too close to other parts of the stitch line.
In a case where a user unskilled in the sewing operation sews the stippling stitch in the course of free-motion sewing with a sewing machine that employs the aforementioned conventional technique, the user can perform sewing in such a manner as to form stitches with a uniform stitch length. However, the user may still find it difficult to perform sewing while taking care not to form a stitch line with an overlapping part, and may even fail to do so. In such a case, the user may be involved in a troublesome task, because he must stop sewing, cut off a thread, remove the failed stitches, and then restart sewing.